MAPT and Alzheimer disease: AD is pathologically defined by the presence of two major types of pathologic brain inclusions: 1) extracellular amyloid-β (Aβ) deposits in the form of plaques and cerebral amyloid angiopathy and 2) intracellular aggregates of tau protein that comprise neurofibrillary tangles (NFT) and neuropil threads [11, 40].